1. Field of the Invention
The present invention relates to an energy absorber, and more particularly to a friction-damping energy absorber; the stiffness, the damping effect and the deformation of the friction-damping energy absorber can be controlled to provide an automatic adjustment function and adaptive characteristics to separately achieve optimum functions for multiple performance objects at multiple levels of vibrations.
2. Description of Related Art
Conventional energy absorbers are commonly mounted on large objects, such as buildings, bridges or machines to provide shock-absorbing and shock-suppressing effects to the objects and to absorb the energy and shocks generated during earthquakes. U.S. Pat. No. 5,655,756 (hereinafter referred to as the referenced case) discloses a conventional energy absorber (Lead Rubber Bearing, LRB) comprises a core post, two supporting boards, multiple metal layers, and multiple rubber layers. The supporting boards are mounted respectively on two ends of the core post, and are securely connected to the ground and a large object respectively. The metal layers and the rubber layers are alternately mounted between the supporting boards. When an earthquake occurs, a shock-absorbing effect can be provided by the deformations of the metal and the rubber layers to reduce the damage caused by the earthquake.
However, the core post of the conventional energy absorber of the referenced case is made of lead. The lead core post may be deformed during the earthquake to absorb the vibration energy of the earthquake, and the deformation of the lead core post will generate heat. Therefore, the temperature of the lead core post of the referenced case will rise to about 350° C., which exceeds the melting point of lead, about 327° C., by the repeated deformation during the earthquake, and the high temperature easily causes the melting of the lead core post, and lead is a toxic heavy metal that will impact the environment. Furthermore, the rubber layers and the lead core post of the conventional energy absorber are easily damaged in the overheating event. In addition, the high temperature also easily decreases the structural strength of the energy absorber, such that the shock-absorbing effect of the conventional energy absorber is also reduced. In addition, even if the temperature does not reach the melting point of lead, the materials (including lead and rubber) are also softened by the temperature, and this will reduce the structural strength and the shock-suppressing and shock-absorbing effects of the conventional energy absorber.
In view of the above-mentioned problems and shortcomings of the conventional energy absorber, the energy absorber that is made of lead has gradually been banned or renounced from use. It is that the world has tried thinking about other shock-absorbing materials or energy absorption mechanism by which it needs to solve the energy absorption, the environmental protection, and other issues. One of the solutions is to remove the lead core post, but the shock-absorbing effect is inadequate and this will cause the energy absorber to have too large displacement. If the conventional energy absorber is used with other dampers such as a hydraulic damper, the cost is expensive. In addition, it is not only cost-ineffective, but also requires a large space to accommodate the conventional energy absorber and the other dampers, and this will cause problems of use and needs to be improved.
To overcome the shortcomings, the present invention tends to provide a friction-damping energy absorber to mitigate or obviate the aforementioned problems.